MSN in blackberry out the message"service not available for this device"

if you often use MSN on your blackberry? or even you can not separate them with MSN as a means of communication with friends or your working relationship, although we often use MSN if MSN is not necessarily that we use on our blackberries will run normally, and MSN sometimes on Blackbery we will have a sign error would come out the message "service not available for this device"

how do we